Unaudited Condensed Consolidated Statements of Cash Flows (USD $) In Thousands, unless otherwise specified	3 Months Ended
	Apr. 28, 2012	Apr. 30, 2011
Cash flows from operating activities:
Net loss	$ (13,702)	$ (5,670)
Adjustments to reconcile net loss to net cash used in operating activities:
Depreciation and amortization	5,117	7,437
Stock-based compensation	2,826	3,191
Provision for excess and obsolete inventory	303	167
Provision for (release of) sales discounts and doubtful accounts	149	(44)
Loss on disposal of equipment	34	47
Accretion of contributed leasehold improvements	(69)	(60)
Changes in operating assets and liabilities:
Accounts receivable	(2,544)	(5,936)
Inventories	3,123	(644)
Prepaid expenses and other current assets	(113)	(727)
Other non-current assets	182	15
Accounts payable	(1,605)	(1,343)
Accrued liabilities	392	(3,826)
Other long-term liabilities	(1,019)	839
Net cash used in operating activities	(6,926)	(6,554)
Cash flows from investing activities:
Restricted cash		(5)
Purchases of marketable securities	(10,393)	(20,104)
Sales and maturities of marketable securities	54,662	17,571
Purchases of software, purchased IP, equipment and leasehold improvements	(2,667)	(5,233)
Net cash provided by (used in) investing activities	41,602	(7,771)
Cash flows from financing activities:
Net proceeds from exercise of employee stock options	55	1,164
Net cash provided by financing activities	55	1,164
Effect of foreign exchange rate changes on cash and cash equivalents	36	248
Increase (decrease) in cash and cash equivalents	34,767	(12,913)
Cash and cash equivalents at beginning of period	44,283	72,732
Cash and cash equivalents at end of period	79,050	59,819
Supplemental disclosure of cash flow information:
Cash paid for income taxes	$ 468	$ 197